Pneumonia vs. Bronchitis: Field Assessment

The Clinical Distinction

Without chest X-ray, the distinction between bronchitis and pneumonia relies on history and physical examination — particularly auscultation.

Acute Bronchitis

Definition: Infection of the bronchial airways without consolidation of lung parenchyma.

Typical presentation:

• Productive cough lasting 1-3 weeks
• Cough may produce yellow or green sputum (this does NOT indicate bacterial infection or require antibiotics — sputum color is unreliable for bacterial vs. viral differentiation)
• Fever absent or low-grade (< 38°C), brief (< 24 hours)
• No significant dyspnea (shortness of breath at rest)
• Breath sounds: diffusely decreased, or scattered rhonchi (rumbling sounds from mucus in large airways) that clear with coughing. No focal crackles or dullness.

Cause: 90%+ viral (rhinovirus, influenza, parainfluenza, RSV). Bordetella pertussis causes whooping cough, which can be severe and requires antibiotics.

Treatment: Bronchitis in an otherwise healthy adult does not require antibiotics. Supportive care: cough suppressant (dextromethorphan 15-30mg every 4 hours), guaifenesin for productive cough, adequate fluids, rest.

Community-Acquired Pneumonia (CAP)

Definition: Infection of the lung parenchyma with consolidation or infiltrate, acquired outside of a hospital.

Typical presentation:

• Cough (productive or dry)
• Fever > 38°C (100.4°F), sustained beyond 24-48 hours
• Chills, rigors (shaking chills — highly specific for bacterial pneumonia)
• Dyspnea (shortness of breath) at rest or with minimal exertion
• Pleuritic chest pain: sharp, stabbing pain that worsens with deep breath or coughing (indicates pleural involvement)
• Fatigue and malaise out of proportion to a simple viral illness

Focal signs on auscultation:

• Crackles (rales): Fine, late-inspiratory crackling sounds — the sound of fluid-filled alveoli opening. The most sensitive sign of consolidation. Often described as "walking on fresh snow" or "velcro being pulled apart."
• Dullness to percussion: Percuss the chest wall (tap with middle finger, listen for hollow drum sound vs. flat dull sound). Dullness over an area of the chest indicates consolidation or fluid (pleural effusion). Normal chest is resonant (hollow).
• Bronchial breath sounds: Normally, breath sounds are "vesicular" — soft and rustling. Over a consolidated lung segment, breath sounds become louder and harsher, similar to the sound heard over the trachea. This is bronchial breathing and is pathognomonic for consolidation.
• Egophony: While auscultating, ask the patient to say "E." Over consolidated lung, the "E" sound is heard as "A." This indicates consolidation.

A single area of crackles + fever + cough + dyspnea = treat for pneumonia even without X-ray.

Severity Assessment

The PORT/PSI and CURB-65 scores guide pneumonia severity. The simplified CURB-65 is practical in field settings:

Score 0-1: Mild pneumonia. Oral antibiotics. Home management is usually appropriate. Score 2: Moderate pneumonia. Oral antibiotics with close monitoring. Consider evacuation. Score 3-5: Severe pneumonia. IV antibiotics required. Hospitalization indicated. Evacuation urgently.

Antibiotic Selection

Typical Pneumonia (Streptococcus pneumoniae — most common bacterial cause)

Amoxicillin: 1g three times daily × 5-7 days. First-line for typical community-acquired pneumonia in patients with no penicillin allergy.

Augmentin (amoxicillin-clavulanate): Better for polymicrobial coverage. 875mg/125mg twice daily × 5-7 days.

Cephalexin: 500mg 4x/day × 7 days — alternative for penicillin-allergic patients (if not anaphylaxis-type allergy).

Atypical Pneumonia (Mycoplasma, Chlamydia pneumonia, Legionella)

More common in younger adults. Often a "walking pneumonia" — patient is sick but ambulatory, with prolonged dry hacking cough, headache, and flu-like symptoms. Responds poorly to beta-lactam antibiotics (amoxicillin, cephalexin).

Doxycycline: 100mg twice daily × 5-7 days. Covers both typical and atypical organisms. First-line in most field settings where you cannot distinguish the two.

Azithromycin: 500mg day 1, then 250mg days 2-5. Also covers both typical and atypical. Shorter course.

When to Use Which

Doxycycline or azithromycin are the most practical single-antibiotic choices for community-acquired pneumonia in the field because they cover both typical and atypical organisms. In a setting where you cannot perform blood cultures or laboratory testing, choose one of these rather than amoxicillin alone.

Combination therapy for severe pneumonia (beta-lactam + atypical coverage): Amoxicillin/clavulanate + azithromycin provides broader coverage for more severe disease.

Complications to Watch For

Pleural Effusion

Fluid accumulating around the lung (in the pleural space).

Signs: Dullness to percussion over one side, reduced or absent breath sounds over the area of effusion, dyspnea out of proportion to the pneumonia.

Uncomplicated parapneumonic effusion (reactive fluid without infection): usually resolves with antibiotic treatment.

Complicated effusion or empyema (pus in the pleural space): requires drainage. Signs that suggest empyema: failure to improve on antibiotics, new fever while on treatment, very ill appearance. Evacuation required.

Lung Abscess

Cavitation within consolidated lung tissue. Usually from aspiration pneumonia (in alcoholics, post-seizure patients, anyone who aspirated vomit).

Signs: Failure to improve, foul-smelling sputum, hemoptysis.

Treatment: prolonged antibiotics (4-6 weeks), clindamycin for anaerobic coverage. Rarely requires surgical drainage if antibiotic responsive. Evacuate.

Aspiration Pneumonia

A specific variant from inhalation of oropharyngeal contents or gastric material.

Risk factors: Decreased consciousness (alcohol intoxication, seizure, stroke, sedation), dysphagia, poor dental hygiene.

Distinguishing features: Presentation typically 2-4 days after aspiration event. Often right lower lobe (the dependent lobe in most aspiration positions). Polymicrobial including anaerobes.

Treatment: Amoxicillin-clavulanate 875/125mg twice daily × 7-10 days. Clindamycin 300mg 4x/day × 7-10 days for penicillin-allergic patients. Metronidazole in combination with another antibiotic for severe aspiration pneumonia.

Pneumonia in High-Risk Patients

These groups require earlier and more aggressive intervention:

Elderly (> 65): More likely to present without fever. Confusion may be the primary or only sign. Higher mortality. Lower threshold for evacuation.

Chronic lung disease (COPD, asthma): Pre-existing impaired respiratory reserve. Exacerbations can progress rapidly.

Immunocompromised (HIV, chemotherapy, diabetes): Unusual organisms (PCP in HIV, fungal pneumonia). Standard antibiotics may not cover.

Children under 5: Higher risk for serious bacterial pneumonia. Respiratory rate is the key indicator — rates above age norms warrant antibiotics. Amoxicillin 90mg/kg/day divided 3x daily is first-line for pediatric pneumonia.